S5970 An Unexpected Infection: Diagnosing a Liver Abscess in a Young, Healthy Adult

Introduction: A pyogenic liver abscess (PLA) is an uncommon pathology that can develop from a wide spectrum of clinical sources. Pathogenesis is most typically seen as abscess development in the context of underlying biliary tract disease such as gallstone or malignant obstruction, direct spread from penetrating trauma, seeding from an arterial source, or portal pyemia from bowel leakage or peritonitis. This case serves as an example of PLA of cryptogenic origin. Case Description/Methods: The patient was a 38-year-old White man with a history of hypertension and gastroesophageal reflux disease who presented with worsening right upper quadrant (RUQ) pain and fevers. Six weeks prior, he had malaise and diarrhea and was diagnosed with mononucleosis. Symptoms persisted with RUQ pain, poor oral intake, and 30 lb weight loss. He also had flank pain and dark urine; renal ultrasound showed an incidental liver lesion. He developed fevers and presented to the Emergency Department. Labs: white blood count 11.9, Alk Phos 428, alanine aminotransferase 91, aspartate aminotransferase 48, T-bili 0.5, Hgb 10.5. Computed tomography showed 6 × 8 × 9 cm thick-walled cavitary mass in posterior right hepatic lobe, consistent with hepatic abscess. Blood and stool cultures were negative; HIV was negative. The patient had no prior history of travel outside of the ultrasound, alcohol, or drug use. MRCP and colonoscopy were unremarkable. Patient was started on zosyn and underwent interventional radiology-guided drainage with cultures positive for E. coli. Antibiotics were deescalated to flagyl and TMP/SMX. Following drain placement, the patient's symptoms significantly improved and he was discharged with drain intact and a 4-week antibiotic plan. Discussion: Cryptogenic PLA is a rare pathology with a worldwide incidence of 1 in 50,000 individuals. However, the vast majority of these cases occur within Asia, with Klebsiella pneumoniae as the most frequent pathogen. The role of screening colonoscopy in patients with cryptogenic PLA is crucial as this population has been found to have increased risk for colorectal cancer. Similar to those with colorectal cancer, patients with inflammatory bowel disease have a pathophysiology that involves inflammation leading to disruption of the colonic mucosal barrier. While this patient’s colonoscopy was grossly normal, he was taking omeprazole outpatient. Though poorly understood, studies both abroad and in the U.S. have shown that proton pump inhibitors are associated with increased risk of developing PLA. The scope of this association remains unclear, and this case serves as an example of the need for further studies examining the relationship of PPIs in patients with PLA without apparent origin.